After some debate over whether the difference between iPhone 6s and iPhone 6s Plus models made with Samsung or TSMC chips may impact battery life, Apple has offered its own take on the matter:

Our testing and customer data show the actual battery life of the iPhone 6s and iPhone 6s Plus, even taking into account variable component differences, vary within just 2-3% of each other.”

That 2-3% difference may be greater than some suspected, myself included, considering how tight battery life on iPhones can be with moderate to heavy usage. Apple’s full statement (via Ars Technica) actually addresses the type of battery tests many testers reference when measuring performance as being unrealistic:

Certain manufactured lab tests which run the processors with a continuous heavy workload until the battery depletes are not representative of real-world usage, since they spend an unrealistic amount of time at the highest CPU performance state. It’s a misleading way to measure real-world battery life.

Still, some benchmark tests have flagged some measurable differences between iPhones made with chips from different manufactures including varying performance scores and cooling levels.

In practice, these differences are likely not noticeable in the same way as the ones between iPhone generations year-over-year, but Apple does acknowledge that the current iPhone 6s and 6s Plus models aren’t totally on par with each other even if the difference is small. But the difference is apparently regardless of what chip variant you have and varies from iPhone to iPhone in general, even past generations. Apple didn’t, however, specifically address any performance differences between the chip variants being used.

Analysis from Chipworks revealed a week ago that the Samsung-made A9 chip which powers some iPhone models this year is 10% smaller than the TSMC-made version. Apple opted for a mix of suppliers for its A-series chip this year likely to ensure meeting demand.

Apple’s full statement below:

With the Apple-designed A9 chip in your iPhone 6s or iPhone 6s Plus, you are getting the most advanced smartphone chip in the world. Every chip we ship meets Apple’s highest standards for providing incredible performance and deliver great battery life, regardless of iPhone 6s capacity, color, or model.

Certain manufactured lab tests which run the processors with a continuous heavy workload until the battery depletes are not representative of real-world usage, since they spend an unrealistic amount of time at the highest CPU performance state. It’s a misleading way to measure real-world battery life. Our testing and customer data show the actual battery life of the iPhone 6s and iPhone 6s Plus, even taking into account variable component differences, vary within just 2-3% of each other.